Flying boat



Jan. 10, Ro 1,893,908

FLYING BOAT Original Filed Sept. 19. 1927 Patented Jan. 18, 1933 p! NITED STAT ADOLF ROHRBACH, OF BERLIN, GERMANY, ASSIGNOR T0 ROBE-EACH PATENTS COR- PORATION, A CORPOBATIGN OF DELAWARE FLYING BOAT Application filed September 19, 1927, Serial No. 220,341, and in Germany September 22, 1926. Renewed May 18, 1932.

The object of the invention is a hydro-airplane characterized by the combination of supporting wings of strongly pronounced trapezoidal shape on which the engines are supported by open lying struts, with a floating system consisting of a fuselage designed as a boat and two lateral supporting floats arranged near the total centre of gravity of the airplane. All three floating bodies have preferably a bottom form adapted for deviating the water at the border downwards.

While it is not novel to use slightly trapezoidal-shaped wings for monoplanes, the application of the strongly pronounced trapezoid-shape reduces the surfaces of the outer ends of the wings of a hydroplane so that it is influenced in a correspondingly smaller degree by the side wind. The diminution of the danger of capsizing may be considered as a means of imparting to a hydroplane good sailin properties, even to such a degree that it may be suited for the high-sea service.

The invention resides further in a special floating system co-operative with the sharply tapered wings in a manner to enhance the sailing qualities of the craft and to diminish to a marked degree the tendency to capsize thereby. This floating system consists on the one hand of the fuselage of'the airplane designed as a boat and on the other hand of two floats arranged close to its sides. These three bodies form in the proximity to the total centre of gravityof the airplane a rather compact floating device in which both a hydrostatic and hydrodynamic effect is exercised by the side floats: the corresponding water displacement gives the airplane a great metacentric height when compared with the sole arrangement of the fuselage so that even in rough weather the hydroplane rests rather quietly on the water. The endeavour to reduce as far as possible the influence of. the side wind on the boat, is still further promoted by mounting the screw enginesfar above the supporting planes on open lying struts. The detrimental effect of wind forces in those arrangements where the engine located far above the supporting wing surface is connected to the wing by. means of a deep bed or a casing, is thus avoided.

For conserving the balance of the floating hydro-airplane it is a further advantage to give the vertical and horizontal tail planes a distinctly tapering form towards their outer ends so that a turning moment exercised by the side wind-on the longitudinal axis of the airplane, has a relatively small bearing.

Special attention must also be given to the starting devices for hydro-airplanes as it is incomparably more diflicult to take off from the water than from the land. Especially important, however, are good starting devices for high-sea airplanes because these hydroplanes must be able to overcome the high waves of the open sea and to take ofl' without difliculty. v

The invention meets these requirements owing to the fact that the floats arranged near the sides of the boat have a hydrodynamical lifting power which from the beginning of the start up to the critical velocity help the boat to takeoff from the water untilwhen or after exceeding the critical velocity-the floats are lifted from the water sooner than the fuselage.

Taking off is essentially facilitated by the wings which owing to their favorable form have a maximum lifting power. i

. Another characteristic feature of the invention consists in that an atleast threeengined power plant is used,,the central engine being located above the fuselage; the two lateral engines being supported substantially vertically above the two stabilizing floats. The screws which are connected with theenginesby means of short shafts, are ar ranged as pushers, so hat the slip stream is freelyflowing and the very important air flow over the wing nose is not impaired 0wing to the-screws being arranged above the rear part of the wing surface.

Moreover, with this arrangement of pusher screw engines the airscrews are efficiently protected against spray water both at start.

and on alighting, and the great depth of the wing root acts as a protective screen for the driving means. The effect of spray water is further reduced owing to the engines being located above the floats.

Fig. 1 shows a modification of the object of the invention in front view, Fig. 2 shows same in plan view and Fig. 3 in side elevation.

The flying machine is a hydro-monoplane whose wing a tapers distinctly from the inner end towards the outer end, e. g., in the ratio 4:1. The screw engines 6 have no surface connection and rest above the wings on strut-s c. The fuselage d of the airplane consists of a boats hull with steps arranged on the bottom. Its bow ends in a sharp edge e and has an upwardly directed stem f. Close to the sides of the fuselage or boat and in the proximity to the total centre of gravity w of the airplane are the two side floats g which have a great share in carrying the weight of the machine so that a great metacentric height results for the flying boat. It is convenient to have the centre of pressure 3 of the floats, when the boat moves slowly on the water, a little in front of the total centre of gravity 00 of the airplane. The engines 6 drive pusher screws 1". The total center of gravity :0 is essentially located above the first step a of the hull (Z.

The bottom of the hull d and the float g in its front part are keeled so that the sharply inclined symmetrical planes of the bottom deviate the water downwards at the border It. For attaining a smooth alighting on the water the keel line 2' shall be considerably deeper than the border. For the fastening of the side floats g serve struts is,

'm of which the struts leading to the fuselage d are horizontally arranged above the water level, whilst the struts m leading to the wing are arranged in the proximity of the lateral struts a supporting the lateral the weight of the engine is immediately transmitted to the floats. a are the vertical tail planes which like the wings have a strongly tapering form towards their tips. The horizontal tail planes (1 are braced to the hull by two struts p. Deviating from the construction of our drawing the side floats can also be connected solely to the fuselage or solely to the wings orthey can be built together with hese parts.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed I declare that what I claim is 1. A seaplane having in combination long monoplane wings which taper in the ratio of about 4. 1 from the roots towards their tips, aboat shaped hull located substantially underneath the wings and having compartments to accommodate the crew and the cargo, the wings and the hull forming the seaplane cell, driving means for the seaplane comprising driven air screws, said driving means being disposed above the cell and essentially centrally thereof and braced against said cell, the air screws being located in the shelter of said cell, said hull carrying the vertical and horizontal tail planes, and lateral floats close to the hull in the region of the center of gravity of the craft, said floats being designed to give the craft an adequate metacentric height when afloat and together with the hull constituting means of hydrodynamical buoyancy when the craft is traveling at speed.

:2. A seaplane as claimed in claim 1, where in the vertical and horizontal tail planes have a pronounced taper towards their outer ends.

3. A seaplane as claimed in claim 1, wherein the engines are braced against said cell by spaced struts.

4. A monoplane flying-boat of the character set forth in claim 1 wherein the boat-body is provided with a high stem substantially vertically disposed, said body having a step, the bottom forward of said step being formed with a pronounced keel and chines located at a considerably higher level than the heel, with downwardly opening rounded grooves at the chines terminating close to the bow point, the vertex of the grooves being located at a higher level than the chines, the lateral floats having bottoms with chines located at a higher level than the heels and at said chines downwardly opening rounded grooves.

5. In a hydro-aeroplane of the monoplane type having a wing which has a pronounced taper of about 4 1 from the root towards the tips an aileron from the trailing edge, a'system of floats consisting of a central boat and two displacement and. hydro-planing floats disposed in the vicinity of the total center of gravity of the craft and on opposite sides of the boat, the boat carrying the horizontal and vertical tail planes and having at least one step in the vicinity of the total center of gravity, the boat body having a sharply V- shaped bow and a bottom which is carved in the vicinity of the chines, the latter in the vicinity of the step being situated at a lower level than the vertex of the curvature and at a higher level than the heel of the bottom.

6. A hydro-aeroplane of the character set forth in claim 5 including driving engines arranged above the wings and the fuselage, said engines being supported by struts and the engines being braced in part by struts against the wings.

7. A hydro-aeroplane of the character set forth in claim 5 wherein the lateral floats are also of pronounced V-shape with their chines disposed above the level of the keelsand their bottoms having a concave curvature in the vicinity of the chines, the vertex of said curvature being located at a higher level than the chines.

8. A hydro-aeroplane of the character set forth in claim 5 wherein the craft is of the high-winged type with at least some of air screw driving engines disposed above the wings and supported by struts, the engines being braced in part by struts against the wings, and a tail unit including a vertical tail plane tapering from the stern of the boat upwards and a horizontal tail plane which tapers towards the tips and is carried by said vertical tail plane.

9. A hydro-aeroplane of the character set forth in claim 5 including at least three power plant units disposed side by side, each unit consisting of an engine with a pusher screw, the engines being disposed above the air craft cell formed by the Wings and the boat and braced against said cell by means of struts, said pusher screws being located above said cell and protected by the latter against water.

10. A hydro-aeroplane of the character set forth in claim 5 including at least three power plant units disposed side by side, each unit consisting of an engine with a pusher screw the engines being disposed above the air craft cell formed by the wings and the boat and braced against said cell by means of struts, one of the units being disposed directly above the boat while the other units are disposed on the sides above the wings, said pusher screws being located above said cell and protected by the latter against water.

11. A hydro-aeroplane of the character set forth in claim 5 including at least three power plant units disposed side by side, each unit consisting of an engine with a pusher screw, the engines being disposed above the air craft cell formed by the wings and the boat and braced against said cell by means of struts, one unit being disposed above the central boat structure, and the two other engines being arranged at opposite sides thereof and substantially above the side floats, said pusher screws being located above the cell and pro tected by the latter against water.

12. A hydro-aeroplane of the character set forth in claim 5 including at least three power plant units disposed side by side, each unit consisting of an engine with a pusher screw, the engines being disposed above the air craft cell formed by the wings and the boat and braced against said cell by means of struts, one unit being disposed above the boat, the other two units being disposed laterally thereof above the wing root, said wing root having a considerable depth, said pusher screws being located above said cell and protected by the latter against water.

13. A hydro-aeroplane of the character set forth in claim 5 including at least three power plant units disposed side by side, each unit consisting of an engine with a pusher screw, the engines being disposed above the air craft cell formed by the wings and the boat and braced against said cell by means of struts, the central unit being located above the boat structure and the other units being disposed on opposite sides thereof and carried by struts engaging the upper surface of the wing at points above the lateral floats, the latter being carried by struts engaging the under surface of the wing at points substantially underneath the engine units, said pusher screws being located above said cell and protected by the latter againstwater.

1a. A seaplane having in combination tapering wings with comparatively deep roots, a hull located substantially under the wings, said hull and said wings constituting the seaplane cell, driving means comprising screws for the seaplane, said driving means being disposed above the cell central thereof and braced against said cell, the screws being located in the shelter of said cell, said hull carrying vertical and horizontal tail planes, lateral floats close to the bull in the region of the center of gravity and so disposed as to give the plane an adequate metacentric height when afloat and together with the hull constituting means of hydrodynamical buoyancy when the plane is traveling at speed.

15. A monoplane flying boat of the character set forth in claim 1 L wherein the boat body is provided with a high stem substantially vertically disposed, said body having a step, the bottom forward of said step being formed with a pronounced heel and chines located at a higher level than the keel, grooves being provided at the chines terminating close to the bow and the vertices of the grooves being at a higher level than the chines, the lateral floats having bottoms with chines located at a higher level than the heels, rounded grooves being provided at the chines.

16. In a hydro-aeroplane of the monoplane type having a wing with a pronounced taper from the root towards the tips, an aileron from the trailing edge, a system of floats consisting of a central boat and a pair of displacement and hydroplaning floats arranged in the vicinity of the center of gravity of the plane, one at each side of said boat, said boat having a step at or about the center of gravity of the plane, the boat having a pronounced V-shaped bow and With its bottom curved in the vicinity of the chines, said chines in the vicinity of the step being at a lower level than the vertex of the bottom gravity but at a higher level than the keel.

17. A hydro-aeroplane as set forth in claim 16 wherein the craft is of the highwinged type and provided with a plurality of motors or driving engines, certain of said engines being supported by struts above the wing and braced by struts against the wing, and a tail unit including a vertical tail plane and a herizonta tail plane carried by said vertical tail plane.

18. A hydro-aeroplane of the character set forth in claim 16 and provided with three power units, each comprising an engine and a screw, one of said power units being arranged centrally above the boat and the other power units being disposed at the sides of the central unit, the screws being located above the cell constituted by the wing and the boat, said screws being shielded. from water by said cell.

In testimony whereof I have signed my name to this specification.

ADOLF ROHRBACH. 

